Analysis of Oxidized <Emphasis Type="Italic">p</Emphasis>-GaN Films Directly Grown Using Bias-Assisted Photoelectrochemical Method

A bias-assisted photoelectrochemical oxidation method was used to oxidize p-GaN directly. Secondary-ion mass spectrometry and x-ray photoelectron spectroscopy were used to analyze the grown films, confirming that the p-GaN can be oxidized using the bias-assisted PEC oxidation method. In addition, x-ray diffraction was used to analyze the crystalline phase of the grown films annealed at different temperatures. After annealing the oxide films at 700°C in O₂ ambient for 2 h, the oxidized p-GaN films were converted from amorphous to the β-Ga₂O₃ crystalline phase.